Thermostatic circuit-closer



(No Model.)

W. S. JOHNSON.

THERMOSTATIO CIRCUIT cLosnRf No. 364,518. Patented June '7, 1887.

UNITED: STATES PATENT OFFICE.

WARREN S. JOHNSON, OF MILWAUKEE, WISCONSIN.

THERMOSTATIC CIRCUIT-CLOSER.

SPECIFICATION forming part of Letters Patent No. 364,518, dated June 7, 1887.

Application filed July 50, 1886. Serial No. 209,561. (No model.)

To all whom it may concern:

is employed to open and close an electric cir-,

cuit by coming in contact at its free end with one or more contact-points.

The aims of the invention are to simplify and cheapen the construction, to provide for accurate and instantaneous adjustments of the instrument, so that it will close the circuit at one temperature or another, as demanded, and

to prevent the accidental closing of the circuit.

Referring to the accompanying drawings, Figurel is a perspective view of my instrument. Fig. 2 is a similar view of the same looking from the rear. Fig. 3 is a vertical cross-section through the adjusting devices.

Fig. 4:,is a vertical section through the contact'points and stops.

In constructing my instrument I provide a bar or body, A, of wood or other suitable material which will remain unaffected by the ordinary changes of temperature. I prefer to employ a wooden frame or body and a thermometer, B, of ordinary material. To the upper and lower ends of the bar A, I secure metallic plates 0 and D, having their extremities curved backward and formed into cars adapted for adjustment to a wall or other sup port. Thus formed these plates serve, in addition to the purposes hereinafter described, as supports or brackets to maintain the body A in position at a distance from the wall.

On the upper plate, 0, is formed a stud or pivot, a, which supports a lever, E, secured firmly to the upper end of the thermostatbar F, so that the pivotal motion of the lever will have the effect of throwing the lower end of the bar F to the right or left. This bar may be of any ordinary construction, such as is a commonly employed in thermostatic instruments; but I prefer to construct the same of two strips of brass and hard rubber riveted or otherwise secured firmly together. By the differential expansion of these two substances of which the bar is formed, under variations of temperature the .bar will be curved either to the right or left, as the case may be.

To the metallic portion of the bar F there is secured a conducting-finger, c, which is eX- L tended downward beyond the bar, as shown,

latter are passed through and adj ustably secured to the twoinsulatedbindingpostsf and g, mounted in the plate D, vas shown. A third binding-post, h, is also attached to the plateD and is in metallic contact therewith. The plate D is in turn in contact, as shown in Fig.

2, with a wire, i, or equivalent conductor at tached to the plate 0. The curvature of the bar F consequent to the variations in temper" ature will throw its finger 0 into contact with one or the other of the points d and e, so that the current may pass from the binding-post h through the plate D, conductor 6, plate 0, lever E, and bar F, and finger 0 to the hind ing-postf or g, as the case may be.

The lever E has one end extended downward and seated in the grooved end of a screw, G, which is in turn seated centrally within a larger screw, H, mounted in a hub or projec tion, K, formed on the plate 0. The larger screw'H is commonly constructed with a thread of greater pitch than the other, and is provided with an operating arm or handle, I, which sweeps over the face of a graduated plate, an, attached to the hub K, or otherwise supported. By turning the central screw, G, the lever may be moved and the thermostat-bar adjusted in relation to the other parts in such manner as to effect the opening and closing of the circuit at the exact temperature required. Being thus adjusted, the screw G remains permanently in position unless some unusual circumstance shall render it necessary to readjust the parts. By turning the handle I and the screw H the latter may be moved inward and outward, carrying with it the screw G, and thereby-changing the position of the lever and of the bar in such manner that the circuit will be opened or closed at a higher or a lower temperature, as occasion may demand.

Under ordinary circumstances the opposing contact-points are so adjusted that the conducting-iinger has but a slight movement in pass ing from one to the other. In view of this fact it is necessary to provide stops to limit between the two contact-points d and e, which ICO the motion of the thermostat-bar, as otherwise an extreme movement of the bar would bend the conducting-finger in such manner that it would touch both contact-points at one time and thus form a short circuit.

I propose to employ steps of any suitable character; but in the present instance I have formed the lower plate or bracket, D, with two arms between which the thermostat passes and by which its motion is restricted.

I commonly employ my thermostats in connection with valves for regulating the supply of steam to heating-coils and to valves for controlling the temperature of buildings, and it is in this connection that the mechanism shown is of peculiar advantage, since it enables the attendant to instantly adjust the de vice to maintain a higher or lower temperature, as may be required.

The employment of the thermometcr-body as a means for supporting,thermostatic devices is advantageous, in that the instrument is given a compact and ornamental appearance,

and in that the thermometer is maintained at all times in position to serve as a guide foradj nsting the thermostat and for determining the accuracy of its operation.

While I prefer to retain the details of coir struction herein shown, it is understood that they may be modified to some extent, and that as regards the adjusting devices the essence of the invention consists in employing with a thermostat devices for effecting two indcpend out adjustments.

Having thus described my invention, what I claim is- 1. In combination with the thermostat-bar and the pivoted arm or lever by which it is a justing-screw, and the indexplate.

In testimony whereoflhereunto set my hand, this 19th day of July, 1886, in the presence of two attesting witnesses.

W'ARREN S. JOHNSON.

Wit nesses;

WM. ll'ELMIUK, C. B. CAYWOOD. 

